Flow characteristics of waxy petroleum residuum

ABSTRACT

A PROCESS FOR PREPARING BLENDING AGENTS FOR IMPROVING THE FLOW CHARACTERISTICS OF HIGH WAX-CONTAINING OILS BY ADDING A C18-C24 CARBOXYLIC ACID HALIDE-FRIEDEL-CRAFTS CATALYST COMPLEX TO STRYENE DISSOLVED IN A SOLVENT AND SIMULTANEOUSLY POLYMERIZING AND ACYLATING SAID STRYENE MONOMER.

April 11, 1972 FLOW CHARACTERISTICS OF WAXY PETROLEUM RESIDUUM OriginalFiled Sept. 20, 1965 CAP/LLARY FLOW, GRAMS/ MINUTE R. J. OTT Er AL3,655,767

FLOW PERFORMANCE OF RANGELY/REOWASH CRUDE BLENOS 50/50 RANGELY/REDWASHBLEND 65/35 RA/VGELY/REDWASH BLEND 3A y 25 l II. I 1

' 2A a v 1 M I a I I 2 4 a a 70 12 /4 zwmoaszv PRESSURE PS/G.

ROY J. OTT

IN VEN TOR! HAROLD N. MILLER I PATL'NT ATTORNEY United States PatentInt. Cl. C07c 49/76 US. Cl. 260592 3 Claims ABSTRACT OF THE DISCLOSURE Aprocess for preparing blending agents for improving the flowcharacteristics of high wax-containing oils by adding a C C carboxylicacid halide-Friedel-Crafts catalyst complex to styrene dissolved in asolvent and simultaneously polymerizing and acylating said styrenemonomer.

This is a division of Ser. No. 488,707, filed Sept. 20, 1965 and nowabandoned.

This invention is concerned with the preparation and utilization of acylpolystyrenes having C C acyl side chains attached to the polystyrenenucleus as blending agents for improving flow characteristics of highwaxcontaining petroleum oils, i.e. crudes, residua, and light fuel oilsand especially petroleum oils which boil above 650 F. and have flowpoints above 75 F.

The pour points of petroleum oils vary widely, for

example, some oils freeze far below zero while others are solid up to 80or 100 F. by virtue of their wax content alone. It is obvious, that thepour point is critical with regard to the flow characteristics and,consequently, the storage, mixing, pumping, etc. of such oil. Thus, pourpoint characteristics are significant to the design and/or operation offacilities for the storage, heat exchange, pumping, etc. of the oil.Naturally, an oil having a high flow point, e.g. above about 75 F. wouldprovide a serious problem relative to the design of the facilitiesmentioned above.

Typical examples of petroleum oils which exemplify the undesirablecharacteristic of having a flow point above about 75 F. are the residualoils set forth in the following Table I:

ice

However, while such Zelten residuum typifies the kind of high-waxcontaining oils which exemplify undesirable flow properties and thelike, such residuum is, in fact, a premium oil as compared to othercrude residua which have much lower pour points. This fact may beillustrated by a comparison of Zelten waxy oil with crude petroleumresidua known as Aramco and Kuwait, as illustrated in the followingTable II TABLE IL-PROCESSING ZEL'IEN CRUDES Heavy fuel oil inspectionsZelten Aramco Kuwait Target Volume percent 680 FVT in crude 35 39 37Inspections on 680 FVT plus:

Gravity, API 22 15 14 Sulfur, weight percent 0. 4 3. 0 4. 2 3. 5Viscosity, SF at 122 F 110 340 40-l75 MN I, weight percent 2. 3 4. 0 3.8 1 7 Conradson carbon, weight percent 4. 5 89 10-11 Flow point, F 10565 65 Hot filtration sed., weight percent 0. 01 0. 02 0. 02 i 0. 15

l Maximum.

'The inspections shown in the foregoing Table H illustrate that theZelten residuum is a premium product per se, as well as a valuableproduct for blending and for improving other heavy fuel oils due to itslow sulfur content, low viscosity, low M'NI (Modified NaphthaInsolubles), and low Conradson Carbon number. Furthermore, it is low inash and vanadium content. These qualities also make Zelten cruderesiduum an excellent cracking stock for obtaining various valuableproducts, such as straight chain olefins, and the like. As presented,the column headed by the notation Target indicates the parameters ofblends which are desirable using said Zelten residuum as a blendingstock, i.e. providing the flow point can be suitably lowered. Forexample, it may be desirable to mix the Zelten residuum in a 50/ 50mixture with the Aramco or Kuwait residuum. While such blending lowersthe wax content, the flow point is generally not sufliciently reduced soas to significantly change the characteristics of the resulting mixtureso as to facilitate the handling thereof.

Thus, while it is found that blending of the extremely highwax-containing petroleum residual oils with other TABLE I.PETROLEUMRESIDUAL OILS Column Number Libya Nigeria Venezuela, Suma- Olol- Santra, Location/Field Zelten Mabruk Raguba Dahra Waha Bomu Ebubu buiJoaquin Minas Flow points of residual F.) 105 110 97 99/100 +100 +100+100 FV'I cut point of residual +680 +680 +650 650 650 650 650 650 650650 blending stocks may lower the wax content, the flow point cannot besatisfactorily reduced without using the specially adapted C -C acylpolystyrene additives to lower the flow point below the 75 F. targetreferred to above in Table I. For example, in the 50/50 Zelten/ Aramcoblend, the addition of only 0'05 Weight percent of the C -C acylpolystyrene additive of the instant 70 invention has been foundsufficient to meet the target of 75 F. flow point. This advantageousaspect will be discussed more fully herein later.

Furthermore, although Zelten crude or similar petroleum oils or mixturescontaining such petroleum oils may have a relatively low viscosity asmeasured by conventional methods as compared to heavy oils of low waxcontent, the handling of the high wax content residuum creates specialdifficulties which are due to the manner in which the oil undergoeschanges in flow characteristics on being subjected to changes intemperature. Generally, the standardized ASTM pour point is reasonablyindicative of how low the temperature of an oil can be decreased and atwhat point it can be satisfactorily made to flow. However, with highwaxy residua, such as the above-described Zelten Oil, the flow pointdetermined by standardized procedure is variable and is further, afunction of prior thermal treatment.

This phenomena may be referred to as a pour gap and is determined whenhigh waxy residua in the presence of natural pour depressants or certainsynthetic pour depressants exhibit pour reversion. This is determined bysubjecting a mixture of residuum and pour depressant through a series ofheating and reheating cycles so as to determine the various pour pointsat reheat temperatures. The following Table III illustrates the effectsof various known additives on the various pour points at reheattemperatures and, consequently, the flow point of Zelten residuum.

containing petroleum residual oils that boil above 650 F. and have pouror flow points above 75 F.

Other objects and advantages will become apparent to one skilled in theart upon a further reading of the following description of the presentinvention.

Accordingly, the present invention is directed to a petroleum oilcomposition having improved flow characteristics, which comprisesessentially a high wax content petroleum oil, e.g. an oil having a flowpoint or pour point above 20 F. and especially a residual oil that boilsabove about 650 F. and has a flow point above about 75 F. improved withrespect to its flow characteristics by incorporating and blendingtherewith an amount of about 0.01 to about 5.0 wt. percent of a C Cpolystyrene having the following general formula:

TABLE III.-EFFECTS OF ADDITIVES ON FLOW POINTS OF 680 F. PLUS VIRGINZELTEN RESIDUUM F. pour points at reheat temperature (TRH= F.)

Averages Concen- TRH: of number Flow Pour Additive tration 100 115 130150 180 0 of tests point 1 gap 680 F. plus virgin Zelten residuum--. 100100 105 105 105 100 95 (3) 105 10 Wax-phenol (ex. 180 mp. wax) 0.30 9097 102 110 85 6O (2) 110 Wax-naphthalene (ex. 180 m.p. wax)- 0.30 83 99109 103 100 65 (4) 109 44 Wax-naphthalene (ex. 150 m.p. wax)- 0.30 98103 105 105 109 90 (4) 109 19 Target pour points 75 75 75 75 75 75 7 lFlow point-maximum pour point obtained after a series of pour pointdeterminations at a series of reheat temperatures.

It is apparent from the foregoing table that; conventional pourdepressants fail to suitably reduce the flow point of the residuuminasmuch as reheating through one or more temperature cycles results inat least one pour point which would be essentially inoperable forcommercial handling of the residuum. Thus, the necessity for a suitableadditive which will effectively reduce the flow point of high waxyresidua through any number of reheat cycles is readily apparent.

In addition, from the foregoing Table III it is apparently necessary tomodify the standard ASTM pour point procedure so as to obtain areproducible and more meaningful measure of flow characteristics and toefiiciently test the high wax-containing residual oils. Accordingly, inthe tests illustrated in the flow point test of Table III, a sample ofoil is first heated to 200 F. and is subsequently cooled to 32 F. beforeit is again heated to an intermediate temperature in the range of 90 to200 F. for testing under the standard ASTM procedure. By putting the oilthrough a temperature cycle series, such as mentioned above, adetermination is made of the pour gap as well as the flow pointcorresponding to the maximum pour point in the series. Such flow pointis the optimum measure achieved as yet for determining how well such oilcan be kept fluid in storage, for pumping, transporting, and the like.

It is accordingly, an object of the present invention to provide anadditive which substantially improves the flow characteristics of highwax-containing petroleum oils.

It is also an object of the present invention to provide improved C -Cacyl polystyrenes which eifectively serve to improve the flowcharacteristics of extremely high waxcontaining petroleum oils such ascrudes, residua and light fuel oilsthat have pour or flow points above20 F.

It is a special object of the present invention to prepare superiorpolystyrenes having C -C acyl side chains attached to the polystyrenenucleus as blending agents for improving the flow characteristics ofextremely high waxwherein R is a C -C alkyl group, and the subscript nis a number from 2 to 50 of the recurring unit in the acyl polystyrene.

Specifically, the present invention is predicated on the discovery thatthe potency of the Clg-C24 polystyrenes are remarkably improved withrespect to their effect on the flow characteristics of extremely highwax-containing petroleum oils when said polystyrenes are prepared by aprocess comprising the steps of: (1) forming a complex of an acylatingacid halide with a Friedel-Crafts catalyst, (2) gradually adding saidcomplex, either continuously or in sequential portions, to a solution ofstyrene monomer and, (3) simultaneously acylating and polymerizing theaddition mixture.

The above-described sequence of steps differs from the method heretoforeemployed to form acyl polystyrenes. This known method comprisesdegrading commercial polystyrene dissolved in an inert solvent, such asorthodichlorobenzene, with a Friedel-Crafts catalyst, e.g., aluminumchloride, and adding to this solution from about 0.5 to 1.0 mole of acarboxylic acid halide-Friedel-Crafts catalyst complex per styrenenucleus present. After all the acid halide-Friedel-Crafts catalystcomplex has been added to the solution of the polystyrene and theevolution of hydrogen halide has stopped, the catalyst is destroyed byaddition of water or alcohol to the reaction mixture. The acylatedpolystyrene product is then taken up in a suitable hydrocarbon solvent,such as heptane or kerosene, and washed with an aqueous alkalinesolution and Water. The solvent may be evaporated to isolate the polymeror the polymer may be dissolved in the solvent before blending with theresidual oil.

Basically, the sole similarity of the process of the present inventionwith that of the prior art is the carboxylic acid halide-Friedel-Craftscatalyst complex employed in each process. This complex is formed bymixing and reacting a C -C carboxylic acid halide, e.g. an acidchloride,

with the Friedel-Crafts catalyst, e.g., aluminum chloride, whichreaction may be represented as follows:

complex The components of the above reaction are employed in molarratios ranging from about 0.9 to 1.1 moles of carboxylic acid halide permole of Friedel-Crafts catalyst and are preferably employed in equimolaramounts. The complex is formed in the presence of a solvent which willdissolve the components and be unreactive with the components and theresulting complex. Typical solvents include, for example, cyclopentane,cyclohexane, the nparaflins, ethylene dichloride, nitromethane,nitrobenzene, orthodichlorobenzene, and the like. The reaction iscomplete in from 15 to 90 minutes when temperatures of from 20 to 70 C.and preferably 20 to 35 C. are employed. The pressure in the reactionzone is not critical and may be varied. Agitation is found to benefitthe rate of reaction between the components.

The carboxylic acid halide reactants which are of particular interestand used in the process of the present invention are the C and C acidhalides, or mixtures thereof. The halides include chlorides, bromides,fluoride, etc., but the chlorides are preferred. These two acidchlorides which are obtained from straight chain carboxylic acids, suchas arachidic and behenic acid, or commercial acid mixtures includingthese two are preferred. The acid halides may be prepared by treatingthe corresponding acid dissolved in a suitable inert solvent, such asthose hereinbefore set forth, and the like, with halogenating agentssuch as phosphorus trichloride, thionylchloride, and the like. Reactiontemperatures are maintained within the range of from about 20 to about80 C. and preferably from 45 to 55 C. and pressures may be varied withina wide, non-critical range.

The Friedel-Crafts catalyst used may be any of this well known type ofcatalyst such as AlCl AlBr AlBr- Cl, AlClBr Al Br Cl, AlBr OH-AlBr AlIBrBF and the like. Aluminum chloride (AlCl is the preferred catalystcomponent employed.

The styrene monomer suitably employed in the present invention maycomprise any commercial grade styrene monomer, i.e. a styrene monomerhaving a purity of about 90% or more. It is preferable, however, toemploy a styrene monomer having a purity greater than 95%. It is withinthe purview of the present invention, however, to employ styrene monomerwhich contains relatively, small amounts of by-product, erg. less than 5wt. percent of styrenes having alkyl groups substituted on the ring,e.g., paramethyl styrene, dimethylstyrene, and the like.

In accordance with the present invention, the acid halide-Friedel-Craftscatalyst complex is gradually added to a styrene monomer solution inorder to effect simultaneous acylation and polymerization reactions.This reaction may be represented as follows:

In elfecting the above-illustrated reaction, the styrene monomerutilized is initially dissolved in a solvent to form a 10 to wt. percentsolution, preferably a 20 to 50 wt. percent solution. The solvent mustbe unreactive with the styrene monomer as well as the acid halide-Friedel-Crafts complex and preferably is a solvent similar to thatemployed in the acid halide-catalyst complex, for example, cyclopentane,cyclohexane, the n-parafiins, ethylenedichloride, nitromethane,nitrobenzene, orthodichlorobenzene, and the like.

In accordance with the invention, the acid halide-Friedel- Craftscatalyst complex is gradually added to the styrene monomer solution,either continuously or in a plurality of sequential portions. The totalpolymerization and acylation reaction period will generally range fromabout /2 to 12 hours and in order to prepare the potent additives of thepresent invention, addition of the acid halide-Friedel- Crafts complexis made over a period of from A to 4 hours, preferably, 2 to 3 hours. Asdisclosed, the complex addition may be effected either continuouslyduring the defined addition period or may be added in from. about 4 toportions which are added sequentially.

The temperature limitations upon the process of this invention arevaried. Broadly, the temperatures range from 2S C. to 100 C. andpreferably from 0 C. to 60 C. Although there is both polymerization andacylation reaction during the initial stages of the process,polymerization of the styrene monomer is principal. During the initialstages, therefore, the temperature of the reaction mixture is adjustedso as to obtain the desired degree of polymerization. In order to allowa greater degree of polymerization and a consequent higher molecularweight of product, the reaction temperature is initially maintained toone within the range of from -25 C. to 60 0., preferably 0 to 50 C. Inthe latter stages of the reaction, wherein the acylation reactionprincipally occurs, the temperatures should be allowed to rise from thetemperature of the initial stage so as to be maintained within the rangeof from about 25 to 100 0., preferably 25 to 60 C. The pressure in thereaction zone is not critical and may be varied within the wide limits.Generally, however, it will be found that atmospheric pressure is quitesuitable for carrying out the reaction.

The proportions of the constituents of the reaction mixture may bevaried widely, e.g., from about 0.5 to 1.0 mole of acidhalide-Friedel-Crafts catalyst complex may be employed per mole ofstyrene monomer. Preferably, the invention contemplates the use ofequimolar proportions of the acid halide-Friedel-Crafts catalyst complexand the styrene monomer.

Reaction of the acid halide-Friedel-Crafts catalyst complex with thestyrene monomer results in a complex consisting of acyl polystyrene andFriedel-Crafts catalyst. In order to prepare the additives of thepresent invention, therefore, this reaction complex is hydrolyzed. Thismay be represented as follows:

The final product of this invention may be blended directly with thehigh wax-containing petroleum oils. Concentrations within the range offrom 0.01% to by weight of the additive material in the petroleum oilswill be operable and will give the desired improvement in flowcharacteristics. Based on economic as well as flow modifying reasons,from about 0.025 to 0.25 wt. percent of the additive is preferablyemployed.

The additives of this invention are found compatible with other additivematerials and may be blended successfully with petroleum oils containingminor amounts of viscosity index improvers, rust inhibitors, oilinessagents, oxidation inhibitors and the like.

The superior additives of the present invention may be understood morefully from the following examples illustrating same.

EXAMPLE I This example serves to illustrate the preparation of a C Cacyl polystyrene in accordance with the method of the present invention.

A C C acid chloride-aluminum chloride complex was prepared by adding40.0 grams of cyclohexane to 72.0 grams of the acid chloride (90% C Cwith agitation. To the resulting mixture was added 28.0 grams ofAlClwith agitation. The reaction mixture was maintained in the range of from22 to 33 C. for a period of 1 hour.

The styrene monomer to be polymerized and acylated was prepared bydissolving 21.0 grams of styrene monomer in 80.0 grams of cyclohexaneWhile maintaining the temperature of the reaction vessel atapproximately 25 C. The acid chloride-AlCl complex prepared above wasgradually added to the styrene-cyclohexane solution continuously over aperiod of 2% hours. During the addition of complex to the styrenesolution the reaction temperature increased from 25 C. to 50 C. Afteraddition of the acid chloride-AlCl complex to the styrene monomersolution was completed, the reaction was continued for an additionalthree hour period while maintaining the temperature of the reactionmixture at approximately 50 C.

The C C acyl polystyrene was recovered by hydrolyzing the reactionproduct with about 200 ml. of a mixture containing'about 75% water, 15%isopropanol and hydrochloric acid. Hydrolysis was effected withagitation at a temperature in the range of about 100150 F. After theevolution of hydrogen chloride ceased, the mixture was allowed to settlefor about /2 hour without agitation and the bottom layer was drawn olf.This hydrolyzed product was then washed with 200 ml. portions of awater-isopropanol mixture about 80% water) until the product attained aneutral pH. The C C acyl polystyrene was then heated under vacuum to 210F. in order to drive ofi the volatiles and isolate the product. Theyield (dialysis residue) was 88% high molecular weight polymeric productas measured by dialysis.

EXAMPLE II The following example illustrates the adverse effect on theyield of high molecular weight polymeric product which results when thesequence of steps necessary to the present invention are not adhered to.

Four hundred and twenty three pounds of a commercially available mixtureof arachidic and behenic acids (C and C acids) and 181 pounds ofn-heptene were charged to a 300 gallon glass-lined reactor. The slurrywas stirred, heated to 50 C., and 66.6 pounds (slight excess) ofphosphorus trichloride added continuously over 20 to 30 minutes. Thereaction mixture was stirred for 11 hours at 50 C., and then allowed tostand 9 hours (overnight) at 50 C., to permit the phosphorus acid tosettle. The phosphorus acid was drained from the reactor and the excessPCl distilled overhead at 50 C., under partial vacuum.

The above acid chloride-n-heptane solution was cooled to about 28 C.,and 167.0 pounds of aluminum chloride was added portion-wise, whilestirring, over /21 hour. The reaction mixture was stirred an additionalhour to complete the formation of the hydrocarbon soluble complex.

A solution of 130.7 pounds of styrene monomer and 130.7 pounds ofn-heptane was added continuously over a period of about 2 hours to theabove acid chloridealuminum chloride complex. The reaction isinstantaneous and is indicated by a change in color (to red-orange), bythe evolution of copious amounts of gaseous HCl, and by a rapid rise intemperature (highly exothermic). The temperature was permitted to riseto 50 C., and maintained at 50 C., by external cooling. After thestyrene addition was completed the reaction was stirred an additional 2hours at 50 C.

The reaction product was hydrolyzed by adding it to 57 gallons of 10%hydrochloric acid solution and 10 gallons of isopropyl alcohol. Thealuminum salt containing acid-water layer was discarded and the organicphase was washed again with dilute HCl followed by 3 clear water washes.The solvent (n-heptane) and residual water were initially stripped outat elevated temperatures under atmospheric pressure and finallycompletely stripped under vacuum. The yield of active product was lessthan 65%. This yield represents a difference in yield of active highmolecular weight polymeric product of 23% when compared with Example I.

EXAMPLE III Acyl polystyrenes made by the process of the presentinvention as illustrated in Example I and made by a process outside thescope of the present invention, i.e., wherein the order of addition ofcomponents and the manner of same is modified, were compared in order toillustrate the vastly improved potency of the additives of thisinvention. In the following table various reheat temperature cycles wereemployed as hereinbefore described in order to test the effectiveness ofthe additives. Such temperature cycles as well as the additiveconcentration employed are set forth in Table IV. The residual oilemployed was Brega residuum which initially boils at a temperature ofabout 650 F. and has a flow point of F.

1 Additive concentration in Brega residuum. 2 Made by process describedin Example I. 8 Made by the process described in Example II.

As will be apparent from an examination of the comparative data reportedin Table IV above, the products of this invention impart a three-foldimprovement in the flow characteristics of the residual oil with whichthey are blended. In other Words it took three times the concentration0.3% of prior art additive to equal the effectiveness of the additive ofthe instant invention. The economic advantages accruing from thisimprovement are readily apparent and need not, it is believed, befurther commented on.

EXAMPLE IV FIG. 1 represents comparative data resulting from tests whichsimulated the handling of high waxy crudes in a pipeline.

The effect of various additives on blends of two specific crude stocksis presented, i.e., Redwash crude from Utah and Rangely crude fromWestern Colorado. The improvement resulting from the additives of thepresent invention is readily apparent from said FIG. 1 wherein typicaldata is set forth in graphical form.

In the various runs, kinematic viscosities at 32 F. were determined withthe Burrell-Severs extrusion viscometer. In this test, 50/50 and 65/35ratios of Rangely/ Redwash crude mixtures were placed in the samplereservoir of the viscometer and subjected to various nitrogen pressuresrepresented as the axis of abscissas in the graph of FIG. 1. Thecapillary diameter of the sample reservoir was 0.074 inch. The resultingflow viscosities, i.e., capillary flow, is presented as the axis ofordinates of said graph. The test temperature utilized, i.e., 32 F. isconsidered representative of winter operations in an unheated,underground pipeline.

Curves 1A and 1B represent the kinematic viscosities of the blendscontaining no additives. Curves 2A and 2B represent the kinematicviscosities of blends which contain 0.05 wt. percent of an additiveproduced in a manner similar to that of Example II, that is, an additiveproduced by a sequence of steps outside the scope of the presentinvention. Curves 3A and 33 represent the kinematic viscosities ofblends which contain 0.05 wt. percent of an additive similar to thatproduced in Example I, that is, an acylated polystyrene of the presentinvention.

From an inspection of the graphical representation of FIG. 1, it isreadily apparent that use of the additives of the instant inventionresults in a remarkable improvement in the full viscosities of crudesunder conditions representative of winter operations.

EXAMPLE V Acyl polystyrenes prepared by the process of the presentinvention, for example, by the process of Example I, and made by aprocess outside the scope of the present invention, for example,according to Example II wherein the order of addition of components,etc., is modified may also be compared employing light fuel oils orother similar petroleum oils. Upon comparison, it is found that similarbeneficial results as hereinbefore illustrated were also encounteredwith light fuel oils.

In this comparison, three identical 50 ton tanks were filled with about40 tons each of 200 sec. Light Fuel Oil ex Esso (Karlsruhe) of 65 F.pour-point. All tanks were equipped with 3 thermocouples. The tankscould be heated by a heating-bell positioned at the bottom thereof. Thetank inlet and otftake was via a telescopic stand pipe in the tankbottom.

The fuel in Tank 1 was left undisturbed for the duration of the test(about 4 months). Upper pour points were carried out on one sample eachweek. Tanks 2 and 3 were left undisturbed for 3 weeks, then heated to160 F. for one day, and then left undisturbed for a further 3 weeks.This cycle was repeated 5 times. During the 5th heating cycle 0.05 wt.percent of each of the acylated polystyrene additives, respectively,were blended in (after first cutting 10 it back with 3-4 times its ownweight of kerosene). The tank contents were recirculated for 2 hours toensure good mixing. Samples were taken during the test period and thepour point determined. The results were as follows:

3 Before heating. 4 After blending 0.05 weight percent into Tanks 2 and3. 5 3 weeks after blending.

From the foregoing it can be concluded that the acylated polystyreneadditive prepared in accordance with the present invention veryeffectively improves the flow characteristics of light fuel oils. Inaddition, no indications of pour point regression occurred in the 3weeks during which the fuel was stored after the additive of thisinvention was added.

It is not intended that this invention be limited to the specificexamples presented by way of illustration. The scope of the invention islimited only by the appended claims.

What is claimed is:

1. A process for the manufacture of an acyl polystyrene blending agentfor improving the flow characteristics of high wax-containing petroleumoils which comprises admixing styrene and an inert solvent for saidstyrene, gradually adding to the resulting mixture a G -C carboxylicacid halide-Friedel-Crafts catalyst complex over a period of from aboutA to 4 hours and simultaneously polymerizing and acylating said styrenemonomer at a temperature within the range of from 25 to 100 C. for atotal period of time ranging from about to 12 hours and recovering saidacyl polystyrene.

2. The process according to claim 1 wherein the complex added is a C -Ccarboxylic acid chloride-aluminum chloride complex and said complex isadded continuously over a period of from about 2 to 3 hours.

3. A process for the manufacture of a blending agent for improving theflow characteristics of extremely high wax-containing petroleum residualoils which boil above 650 F. and have a flow point above F. whichcomprises forming a solution of styrene monomer in an inert hydrocarbonsolvent, gradually adding to said solution over a period of from A to 4hours and at a temperature of from about 0 to about 50 C., an equimolarportion of a complex formed by admixing substantially equimolarproportions of a 'Friedel-Crafts catalyst and a 0 0 carboxylic acidchloride and after said addition simultaneously polymerizing andacylating said styrene monomer at a temperature of from about 25 to 60C. for a total period of time ranging from /2 to 12 hours, andthereafter hydrolyzing the resulting complex formed.

DANIEL D. HORWITZ, Primary Examiner

